Phonogram blank



V. EMERQQM PHONOCRAM BLANK wie@ om. 16, 1918 ulSu'r1511 srarizs' vIcToaH. EMERSON, or NEW YORK, N. Y.,'AssxGNon, BY MmNn nssIoNMENTa- To METALanconnINe mso COMPANY, INC., .nl-'CORPORATION or New YORK.

P HONOGRAM BLANK.

Appnnon and' October 1s, 1919. ,semi No. 331,141.

T0 all whom t may concern.:

,Be it known that l, VICTOR H. EMERSON, a citizen of the United States,residin at the city, county, and State of New Ork, have invented new anduseful Improvements in Phonogram Blanks, of which the followinilis aspecification.

y invention 'relates to apparatus for reducing sound records, and hasfor an oblject the production of a blank that may be employed in forminga record groove adapted to receive undulations upon its upper edgesonly.

I have in a co-pending application, Serial No. 331,146, disclosed aprocess for forming in the top edges of a non-undulatory groove soundundulations by means of an ordinary phonograph reproducing device, andalso for a record, the product of my said process. V While the record ofm co-pending application may be produce by a process emplo ing a simpleform of groove, it is found hig ly advantageous to trace the recordformed therein if'the surfaces adjacent the groove beslightly raised soas to mininnze the mass of material topbe indented in forming the typeof groove hereinabove described,

.. namely, having, its undulatory walls thus limited to the uppersurfaces of the groove. Therefore my present invention described ingeneral terms, comprises a blank for making original sound recordshaving a groove formed with upturned lips at eitherside thereof. Theaccompanying drawings illustrate a preferred form of my invention, ofwhich-- .Figure 1 is a plan view of a blank of` my invention forproducing a disk sound record having the non-undulatory spiral recordshown in the surface thereof; and

Fi 2 is an enlarged fragmentary sectiona view showing in perspective apre ferred vnon-undulatory groove of my invention.

Referring to the drawings, the numeral 1 represents a disk preferablymade of a suitable metal for recording therein sound waves, such ascopper or other metal having a comparatively soft metallic body forreceiving and retaining undulations made by a relativel blunt or roundedtracing point.

Zinc an lead may be employed with good results as the body material ofmy improved blank, yet L find cop er in many res ects superior to othermeta lic substances and use itin preference generally over all othermaterials.

The groove 2 conforms to a lain spiral sunk into the fiat surface of theisk 1 which may have any convenient form as determined by the shape ofthe cutting or tracing'tool with which it may be formed, providing -thatthe top portions 3 of each side wall shall be approximately vertical andextend upwardly beyond the plane of the disk blank so as to form thesharp-edged lip 5v with the surface 4, inclined at approximately 45degrees to the surface 3. .y

.The lip 5 is formed upon both sides of the groove ofsubstantially'equal height and size and is relatively narrow as com aredwith the width of the groove itself.

at is to.

say, the roove properma have greater orr less dept as may suit ot errequirements, but the size and shape of the ridges 5 at respective sidesmust not only be equal and oppositely disposed but will equal in heightand width the average depth lor amplitude` of the sound undulations tobe recorded therein.

Thus in Fig. 2 of the drawing a relatively wide and deep groove isshown, while the fin-like edges are adapted to receive undulationsalong. the top portion of the groove, leaving the bottom free for otheruses or purposes, such for example as the segregation 'of dust particlesandforeign matter that interfere with ideal phonographic reproduction.

The angular pointed edge 5, if made in copper, for example, will,`because of its narrow bod receive to the full depth of its vibrations te indentations of a blunt tracing oint for recording the sound wavestherein; and furthermore by maintaining the declivity of substantially45 degrees for the inclined surfaces 4 the height of the edge 5 may bevaried without fundamentally altering the adaptability to receive thewavev undulations for which it is designed.

The purpose of my disk blank is to provide a blank that may be employedin connection witha'n ordinary phonograph for recording sound wavesthereon. This is accomplished b inserting in the sound box a tracing balor similar reproducin point of greater diametral width than t e distanceseparating the lips 5 of the respective grooves and then placing thedisk blank l upon the turntable of the phonograph.

The Weight of the sound box will carry the ball tracing point of thephonograph down into the material suilicientl)7 in case of recordinglaterally so as to insure itswith a spiral groove having side wallssubstantially vertical at their tops, and extending above the surface ofthe blank and inclined surfaces converging with said extended verticalWalls.

3. In a blank for origina1 sound records a spiral groove having angularridges at its respective sides, said ridges comprising vertical Wallscoincident with the sides of the groove and angular surfaces disposedat'substantially 45 degrees to said Walls.

4. In a blank for original sound records a groove having verticallyprojecting lips at its respective sides, said lips having angular edgeswhose surfaces are disposed at sub4 stantially 45 degrees.

In testimony whereof I have hereunto set my hand.

VICTOR H. EMERSON.

